U.S. patent number 10,298,062 [Application Number 14/037,726] was granted by the patent office on 2019-05-21 for wireless power transmission apparatus and wireless power transmission method.
This patent grant is currently assigned to SAMSUNG ELECTRONICS CO., LTD.. The grantee listed for this patent is SAMSUNG ELECTRONICS CO., LTD.. Invention is credited to Chi Hyung Ahn, Ki Young Kim, Sang Wook Kwon, Jae Hyun Park, Yun Kwon Park, Young Ho Ryu, Keum Su Song.
![](/patent/grant/10298062/US10298062-20190521-D00000.png)
![](/patent/grant/10298062/US10298062-20190521-D00001.png)
![](/patent/grant/10298062/US10298062-20190521-D00002.png)
![](/patent/grant/10298062/US10298062-20190521-D00003.png)
![](/patent/grant/10298062/US10298062-20190521-D00004.png)
![](/patent/grant/10298062/US10298062-20190521-D00005.png)
![](/patent/grant/10298062/US10298062-20190521-D00006.png)
![](/patent/grant/10298062/US10298062-20190521-D00007.png)
![](/patent/grant/10298062/US10298062-20190521-D00008.png)
![](/patent/grant/10298062/US10298062-20190521-D00009.png)
![](/patent/grant/10298062/US10298062-20190521-D00010.png)
View All Diagrams
United States Patent |
10,298,062 |
Song , et al. |
May 21, 2019 |
**Please see images for:
( Certificate of Correction ) ** |
Wireless power transmission apparatus and wireless power
transmission method
Abstract
A wireless power transmission apparatus includes resonators
configured to transmit a power wirelessly to another resonator, and
a controller configured to control a current magnitude and/or a
voltage magnitude of a power to be provided to each of the
resonators. The apparatus further includes a feeder configured to
provide the power to each of the resonators.
Inventors: |
Song; Keum Su (Seoul,
KR), Kwon; Sang Wook (Seongnam-si, KR),
Kim; Ki Young (Yongin-si, KR), Park; Yun Kwon
(Dongducheon-si, KR), Park; Jae Hyun (Pyeongtaek-si,
KR), Ahn; Chi Hyung (Suwon-si, KR), Ryu;
Young Ho (Yongin-si, KR) |
Applicant: |
Name |
City |
State |
Country |
Type |
SAMSUNG ELECTRONICS CO., LTD. |
Suwon-si |
N/A |
KR |
|
|
Assignee: |
SAMSUNG ELECTRONICS CO., LTD.
(Suwon-si, KR)
|
Family
ID: |
51207179 |
Appl.
No.: |
14/037,726 |
Filed: |
September 26, 2013 |
Prior Publication Data
|
|
|
|
Document
Identifier |
Publication Date |
|
US 20140203657 A1 |
Jul 24, 2014 |
|
Foreign Application Priority Data
|
|
|
|
|
Jan 22, 2013 [KR] |
|
|
10-2013-0006815 |
|
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H02J
50/40 (20160201); H02J 7/025 (20130101); H02J
50/80 (20160201); H02J 50/90 (20160201); H02J
50/12 (20160201) |
Current International
Class: |
H02J
50/12 (20160101); H02J 50/40 (20160101); H02J
50/90 (20160101); H02J 7/02 (20160101); H02J
50/80 (20160101) |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
|
|
|
|
|
|
|
2012-65419 |
|
Mar 2012 |
|
JP |
|
10-2004-0065534 |
|
Jul 2004 |
|
KR |
|
WO 2010/035321 |
|
Apr 2010 |
|
WO |
|
WO 2012/073349 |
|
Jun 2012 |
|
WO |
|
WO 2012/169584 |
|
Dec 2012 |
|
WO |
|
Other References
International Search Report dated Apr. 15, 2014 in International
Application No. PCT/KR2014/000538 (3 pages, in English). cited by
applicant .
Extended European Search Report dated Aug. 9, 2016 in counterpart
European Patent Application No. 14743911.1 (8 pages, in English).
cited by applicant .
Communication issued Feb. 7, 2019, issued by the Korean
Intellectual Property Office in counterpart Korean Patent
Application No. 10-2013-0006815. cited by applicant.
|
Primary Examiner: Cavallari; Daniel J
Attorney, Agent or Firm: Sughrue Mion, PLLC
Claims
What is claimed is:
1. A wireless power transmission apparatus comprising: resonators
configured to wirelessly transmit first power to a wireless power
reception apparatus; a controller configured to control a current
magnitude and/or a voltage magnitude of second power to be provided
to each of the resonators; and a conductor configured to provide
the second power to each of the resonators, wherein the controller
is further configured to: receive, by using a communication unit,
information of a voltage and/or a current that are applied to a
load of the wireless power reception apparatus; obtain an
efficiency of the wireless power transmission, based on the
received information and the current magnitude and/or the voltage
magnitude of the second power; and adjust the current magnitude
and/or the voltage magnitude of the second power based on the
efficiency of the transmission.
2. The apparatus of claim 1, wherein the controller is further
configured to: calculate an impedance of an N-port network between
the other resonator connected the N-port network and the resonators
connected to the N-port network; and control the current magnitude
and/or the voltage magnitude based on the impedance.
3. The apparatus of claim 1, wherein the resonators are coupled to
each other, or separated from each other, and wherein the conductor
comprises an inductor.
4. The apparatus of claim 1, further comprising: a communication
circuit configured to receive, from the wireless power reception
apparatus, the information of the voltage and/or the current that
are applied to the load of the wireless power reception apparatus
in response to a test voltage and a test current being applied to
the resonators.
5. The apparatus of claim 4, wherein the controller comprises: one
or more hardware processors configured to: calculate an impedance
of an N-port network between the other resonator connected the
N-port network and the resonators connected to the N-port network,
and the efficiency of the transmission, based on the received
information of the voltage and/or the current; optimize the
impedance based on a predetermined power transmission efficiency;
and determine the current magnitude and/or the voltage magnitude
based on a result of the optimization.
6. The apparatus of claim 5, wherein the one or more hardware
processors is further configured to: change the current magnitude
and/or the voltage magnitude sequentially in a range of the current
magnitude and/or the voltage magnitude that is applicable by the
conductor.
7. The apparatus of claim 5, wherein the one or more hardware
processors is further configured to: change the current magnitude
and/or the voltage magnitude randomly in a range of the current
magnitude and/or the voltage magnitude that is applicable by the
conductor.
8. The apparatus of claim 5, wherein the one or more hardware
processors is further configured to: change the current magnitude
and/or the voltage magnitude based on a lookup table in a range of
the current magnitude and/or the voltage magnitude that is
applicable by the conductor.
9. The apparatus of claim 5, wherein the one or more hardware
processors is further configured to: estimate an optimal current
magnitude and/or an optimal voltage magnitude of the second power
of when the efficiency satisfies the predetermined power
transmission efficiency, based on the impedance and an N-port
matrix relational expression induced in the N-port network.
10. The apparatus of claim 1, wherein each of the resonators
comprises: a first transmission line comprising a first signal
conducting portion, a second signal conducting portion, and a first
ground conducting portion corresponding to the first signal
conducting portion and the second signal conducting portion; a
first conductor connected to the first signal conducting portion
and the first ground conducting portion; a second conductor
connected to the second signal conducting portion; and a capacitor
inserted in series between the first signal conducting portion and
the second signal conducting portion with respect to a current
flowing through the first signal conducting portion and the second
signal conducting portion.
11. A wireless power transmission apparatus comprising: resonators
configured to wirelessly transmit first power to a wireless power
reception apparatus; a controller configured to control a current
magnitude and/or a voltage magnitude of a second power to be
provided to each of the resonators; and a conductor configured to
provide the second power to each of the resonators, wherein each of
the resonators comprises: a first resonator comprising a surface
parallel to an xy plane; a second resonator comprising a surface
parallel to a yz plane; and a third resonator comprising a surface
parallel to a zx plane.
12. A wireless power transmission apparatus comprising: resonators
configured to wirelessly transmit first power to a wireless power
reception apparatus; a controller configured to control a current
phase and/or a voltage phase of the power to be provided to each of
the resonators; and a conductor configured to provide the second
power to each of the resonators, wherein the controller is further
configured to: receive, by using a communication unit, information
of a voltage and/or a current that are applied to a load of the
wireless power reception apparatus; obtain an efficiency of the
wireless power transmission, based on the received information and
the current phase and/or the voltage phase of the second power; and
adjust the current phase and/or the voltage phase of the second
power based on the efficiency of the transmission.
13. The apparatus of claim 12, wherein the controller is further
configured to: calculate an impedance of an N-port network between
the other resonator connected to the N-port network and the
resonators connected to the N-port network; and control the current
phase and/or the voltage phase based on the impedance.
14. The apparatus of claim 12, further comprising: a communication
circuit configured to receive, from the wireless power reception
apparatus, the information of the voltage and/or the current that
are applied to the load of the wireless power reception apparatus
in response to a test voltage and a test current being applied to
the resonators.
15. The apparatus of claim 14, wherein the controller comprises:
one or more hardware processors configured to: calculate an
impedance of an N-port network between the other resonator
connected the N-port network and the resonators connected to the
N-port network, and the efficiency of the transmission, based on
the received information of the voltage and/or the current;
optimize the impedance based on a predetermined power transmission
efficiency; and determine the current phase and/or the voltage
phase based on a result of the optimization.
16. A wireless power transmission method comprising: controlling,
by a controller, a current magnitude and/or a voltage magnitude of
second power to be provided to each of resonators; providing, by a
conductor, the second power to each of the resonators; and
wirelessly transmitting, by the resonators, first power to a
wireless power reception apparatus, wherein the controlling
comprises: receiving, by using a communication unit, information of
a voltage and/or a current that are applied to a load of the
wireless power reception apparatus; obtaining an efficiency of the
transmission, based on the received information and the current
magnitude and/or the voltage magnitude of the second power; and
adjusting the current magnitude and/or the voltage magnitude of the
second power based on the efficiency of the transmission.
17. The method of claim 16, wherein the controlling comprises:
calculating an impedance of an N-port network between the other
resonator connected the N-port network and the resonators connected
to the N-port network; and controlling the current magnitude and/or
the voltage magnitude based on the impedance.
18. The method of claim 16, further comprising: receiving, from the
wireless power reception apparatus, the information of the voltage
and/or the current that are applied to the load of the wireless
power reception apparatus in response to a test voltage and a test
current being applied to the resonators.
19. The method of claim 18, wherein the controlling comprises:
calculating an impedance of an N-port network between the other
resonator connected the N-port network and the resonators connected
to the N-port network, and the efficiency of the transmitting,
based on the received information of the voltage and/or the
current; optimizing the impedance based on a predetermined power
transmission efficiency; and determining the current magnitude
and/or the voltage magnitude based on a result of the optimizing.
Description
CROSS-REFERENCE TO RELATED APPLICATION
This application claims the benefit under 35 USC 119(a) of Korean
Patent Application No. 10-2013-0006815, filed on Jan. 22, 2013, in
the Korean Intellectual Property Office, the entire disclosure of
which is incorporated herein by reference for all purposes.
BACKGROUND
1. Field
The following description relates to an apparatus and a method for
transmitting power wirelessly.
2. Description of Related Art
Research on wireless power transmission has been started to
overcome an increase in inconveniences of wired power supplies, or
the limited capacity of conventional batteries, due to an explosive
increase in various electronic devices including electric vehicles
and mobile devices. One of wireless power transmission technologies
uses resonance characteristics of radio frequency (RF) devices. A
wireless power transmission system using resonance characteristics
may include a source device configured to supply power, and a
target device configured to receive the supplied power.
SUMMARY
In one general aspect, there is provided a wireless power
transmission apparatus, including resonators configured to transmit
a power wirelessly to another resonator, and a controller
configured to control a current magnitude and/or a voltage
magnitude of a power to be provided to each of the resonators. The
apparatus further includes a feeder configured to provide the power
to each of the resonators.
In another general aspect, there is also provided a wireless power
transmission apparatus, including resonators configured to transmit
a power wirelessly to another resonator, and a controller
configured to control a current phase and/or a voltage phase of the
power to be provided to each of the resonators. The apparatus
further includes a feeder configured to provide the power to each
of the resonators.
In still another general aspect, there is also provided a wireless
power transmission method, including controlling a current
magnitude and/or a voltage magnitude of a power to be provided to
each of resonators, and providing the power to each of the
resonators. The method further includes transmitting, by the
resonators, a power wirelessly to another resonator.
Other features and aspects will be apparent from the following
detailed description, the drawings, and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagram illustrating an example of a wireless power
transmission system.
FIG. 2 is a diagram illustrating an example of a wireless charging
environment for a wireless power transmission apparatus.
FIG. 3 is a block diagram illustrating an example of a wireless
power transmission apparatus.
FIG. 4 is a block diagram illustrating another example of a
wireless power transmission apparatus.
FIG. 5 is a diagram illustrating an example of an N-port network of
a wireless power transmission apparatus.
FIG. 6 is a diagram illustrating an example of a target device and
a structure of resonators of a wireless power transmission
apparatus.
FIG. 7 is a diagram illustrating another example of a target device
and a structure of resonators of a wireless power transmission
apparatus.
FIGS. 8 and 9 are graphs illustrating examples of a wireless power
transmission efficiency according to a voltage phase of a power to
be provided to a resonator by a wireless power transmission
apparatus.
FIG. 10 is a diagram illustrating an example of a target device and
an arrangement of resonators of a wireless power transmission
apparatus.
FIG. 11 is a diagram illustrating an example of a structure of a
resonator of a wireless power transmission apparatus.
FIG. 12 is a flowchart illustrating an example of a wireless power
transmission method.
FIGS. 13A and 13B are diagrams illustrating examples of a
distribution of a magnetic field in a feeder and a resonator of a
wireless power transmitter.
FIGS. 14A and 14B are diagrams illustrating an example of a feeding
unit and a resonator of a wireless power transmitter.
FIG. 15A is a diagram illustrating an example of a distribution of
a magnetic field in a resonator that is produced by feeding of a
feeding unit, of a wireless power transmitter.
FIG. 15B is a diagram illustrating examples of equivalent circuits
of a feeding unit and a resonator of a wireless power
transmitter.
FIG. 16 is a diagram illustrating an example of an electric vehicle
charging system.
DETAILED DESCRIPTION
The following detailed description is provided to assist the reader
in gaining a comprehensive understanding of the methods,
apparatuses, and/or systems described herein. However, various
changes, modifications, and equivalents of the systems, apparatuses
and/or methods described herein will be apparent to one of ordinary
skill in the art. Also, descriptions of functions and constructions
that are well known to one of ordinary skill in the art may be
omitted for increased clarity and conciseness.
Throughout the drawings and the detailed description, the same
reference numerals refer to the same elements. The drawings may not
be to scale, and the relative size, proportions, and depiction of
elements in the drawings may be exaggerated for clarity,
illustration, and convenience.
The features described herein may be embodied in different forms,
and are not to be construed as being limited to the examples
described herein. Rather, the examples described herein have been
provided so that this disclosure will be thorough and complete, and
will convey the full scope of the disclosure to one of ordinary
skill in the art.
A scheme of performing communication between a source device and a
target device may be an in-band communication scheme, or an
out-band communication scheme, or a combination of both. The
in-band communication scheme refers to communication performed
between the source device and the target device in the same
frequency band that is used for power transmission. The out-band
communication scheme refers to communication performed between the
source device and the target device in a frequency band that is
different from a frequency band used for power transmission.
FIG. 1 is a diagram illustrating an example of a wireless power
transmission system. Referring to FIG. 1, the wireless power
transmission system includes a source device 110 and a target
device 120. The source device 110 is a device supplying wireless
power, and may be any of various devices that supply power, such as
pads, terminals, televisions (TVs), and any other device that
supplies power. The target device 120 is a device receiving
wireless power, and may be any of various devices that consume
power, such as terminals, TVs, vehicles, washing machines, radios,
lighting systems, and any other device that consumes power.
The source device 110 includes a variable switching mode power
supply (SMPS) 111, a power amplifier 112, a matching network 113, a
transmission (TX) controller 114 (e.g., a TX control logic), a
communication unit 115, a power detector 116, and a source
resonator 131. The target device 120 includes a matching network
121, a rectification unit 122, a direct current-to-direct current
(DC/DC) converter 123, a communication unit 124, a reception (RX)
controller 125 (e.g., a RX control logic), a power detector 127,
and a target resonator 133.
The variable SMPS 111 generates a DC voltage by switching an
alternating current (AC) voltage including a frequency of tens of
hertz (Hz) output from a power supply. The variable SMPS 111 may
output a DC voltage including a predetermined level, or may output
a DC voltage including an adjustable level by the controller
114.
The variable SMPS 111 may control supplied voltage based on a level
of power output from the power amplifier 112 so that the power
amplifier 112 may be operated in a saturation region with high
efficiency at all times, and may enable a maximum efficiency to be
maintained at all levels of the output power. The power amplifier
112 may include class-E features. For example, when a common SMPS
is used instead of the variable SMPS 111, a variable DC-to-DC
(DC/DC) converter needs to be additionally used. In this example,
the common SMPS and the variable DC/DC converter may control
supplied voltage based on the level of the power output from the
power amplifier 112 so that the power amplifier 112 may be operated
in the saturation region with high efficiency at all times, and may
enable the maximum efficiency to be maintained at all levels of the
output power.
The power detector 116 detects an output current and an output
voltage of the variable SMPS 111, and provides, to the controller
114, information of the detected current and the detected voltage.
Additionally, the power detector 116 detects an input current and
an input voltage of the power amplifier 112.
The power amplifier 112 generates a power by converting the DC
voltage output from the variable SMPS 111 to an AC voltage using a
switching pulse signal including a frequency of a few kilohertz
(kHz) to tens of megahertz (MHz). In other words, the power
amplifier 112 converts a DC voltage supplied to a power amplifier
to an AC voltage using a reference resonance frequency F.sub.Ref,
and generates a communication power to be used for communication,
or a charging power to be used for charging that may be used in a
plurality of target devices. The communication power may be, for
example, a low power of 0.1 to 1 milliwatts (mW) that may be used
by a target device to perform communication, and the charging power
may be, for example, a high power of 1 mW to 200 Watts (W) that may
be consumed by a device load of a target device. In this
description, the term "charging" may refer to supplying power to an
element or a unit that charges a battery or other rechargeable
device with power. Also, the term "charging" may refer supplying
power to an element or a unit that consumes power. For example, the
term "charging power" may refer to power consumed by a target
device while operating, or power used to charge a battery of the
target device. The unit or the element may include, for example, a
battery, a display device, a sound output circuit, a main
processor, and various types of sensors.
In this description, the term "reference resonance frequency"
refers to a resonance frequency that is nominally used by the
source device 110, and the term "tracking frequency" refers to a
resonance frequency used by the source device 110 that has been
adjusted based on a predetermined scheme.
The controller 114 may detect a reflected wave of the communication
power or a reflected wave of the charging power, and may detect
mismatching between the target resonator 133 and the source
resonator 131 based on the detected reflected wave. The controller
114 may detect the mismatching by detecting an envelope of the
reflected wave, or by detecting an amount of a power of the
reflected wave.
Under the control of the controller 114, the matching network 113
compensates for impedance mismatching between the source resonator
131 and the target resonator 133 so that the source resonator 131
and the target resonator 133 are optimally-matched. The matching
network 113 includes combinations of a capacitor and an inductor
that are connected to the controller 114 through a switch, which is
under the control of the controller 114.
The controller 114 may calculate a voltage standing wave ratio
(VSWR) based on a voltage level of the reflected wave and a level
of an output voltage of the source resonator 131 or the power
amplifier 112. When the VSWR is greater than a predetermined value,
the controller 114 detects the mismatching. In this example, the
controller 114 calculates a power transmission efficiency of each
of N predetermined tracking frequencies, determines a tracking
frequency F.sub.Best including the best power transmission
efficiency among the N predetermined tracking frequencies, and
changes the reference resonance frequency F.sub.Ref to the tracking
frequency F.sub.Best.
Also, the controller 114 may control a frequency of the switching
pulse signal used by the power amplifier 112. By controlling the
switching pulse signal used by the power amplifier 112, the
controller 114 may generate a modulation signal to be transmitted
to the target device 120. In other words, the communication unit
115 may transmit various messages to the target device 120 via
in-band communication. Additionally, the controller 114 may detect
a reflected wave, and may demodulate a signal received from the
target device 120 through an envelope of the reflected wave.
The controller 114 may generate a modulation signal for in-band
communication using various schemes. To generate a modulation
signal, the controller 114 may turn on or off the switching pulse
signal used by the power amplifier 112, or may perform delta-sigma
modulation. Additionally, the controller 114 may generate a
pulse-width modulation (PWM) signal including a predetermined
envelope.
The controller 114 may determine initial wireless power that is to
be transmitted to the target device 120 based on a change in a
temperature of the source device 110, a battery state of the target
device 120, a change in an amount of power received at the target
device 120, and/or a change in a temperature of the target device
120.
The source device 110 may further include a temperature measurement
sensor (not illustrated) that detects a change in temperature. The
source device 110 may receive, from the target device 120,
information regarding the battery state of the target device 120,
the change in the amount of power received at the target device
120, and/or the change in the temperature of the target device 120,
through communication. The source device 110 may detect the change
in the temperature of the target device 120 based on the
information received from the target device 120.
The controller 114 may adjust voltage supplied to the power
amplifier 112, using a lookup table. The lookup table may be used
to store an amount of the voltage to be adjusted based on the
change in the temperature of the source device 110. For example,
when the temperature of the source device 110 rises, the controller
114 may lower an amount of the voltage to be supplied to the power
amplifier 112.
The communication unit 115 may perform out-of-band communication
using a communication channel. The communication unit 115 may
include a communication module, such as a ZigBee module, a
Bluetooth module, or any other communication module, that the
communication unit 115 may use to perform the out-of-band
communication. The communication unit 115 may transmit or receive
data 140 to or from the target device 120 via the out-of-band
communication.
The source resonator 131 transfers electromagnetic energy 130, such
as the communication power or the charging power, to the target
resonator 133 via a magnetic coupling with the target resonator
133.
The target resonator 133 receives the electromagnetic energy 130,
such as the communication power or the charging power, from the
source resonator 131 via a magnetic coupling with the source
resonator 131. Additionally, the target resonator 133 receives
various messages from the source device 110 via the in-band
communication. The target resonator 133 may receive the initial
wireless power that is determined based on the change in the
temperature of the source device 110, the battery state of the
target device 120, the change in the amount of power received at
the target device 120, and/or the change in the temperature of the
target device 120.
The matching network 121 matches an input impedance viewed from the
source device 110 to an output impedance viewed from a load. The
matching network 121 may be configured with a combination of a
capacitor and an inductor.
The rectification unit 122 generates a DC voltage by rectifying an
AC voltage received by the target resonator 133.
The DC/DC converter 123 adjusts a level of the DC voltage output
from the rectification unit 122 based on a voltage rating of the
load. For example, the DC/DC converter 123 may adjust the level of
the DC voltage output from the rectification unit 122 to a level in
a range from 3 volts (V) to 10 V.
The power detector 127 detects a voltage (e.g., V.sub.dd) of an
input terminal 126 of the DC/DC converter 123, and a current and a
voltage of an output terminal of the DC/DC converter 123. The power
detector 127 outputs the detected voltage of the input terminal
126, and the detected current and the detected voltage of the
output terminal, to the controller 125. The controller 125 uses the
detected voltage of the input terminal 126 to compute a
transmission efficiency of power received from the source device
110. Additionally, the controller 125 uses the detected current and
the detected voltage of the output terminal to compute an amount of
power transferred to the load. The controller 114 of the source
device 110 determines an amount of power that needs to be
transmitted by the source device 110 based on an amount of power
required by the load and the amount of power transferred to the
load. When the communication unit 124 transfers an amount of power
of the output terminal (e.g., the computed amount of power
transferred to the load) to the source device 110, the controller
114 of the source device 110 may compute the amount of power that
needs to be transmitted by the source device 110.
The communication unit 124 may perform in-band communication for
transmitting or receiving data using a resonance frequency by
demodulating a received signal obtained by detecting a signal
between the target resonator 133 and the rectification unit 122, or
by detecting an output signal of the rectification unit 122. In
other words, the controller 125 may demodulate a message received
via the in-band communication.
Additionally, the controller 125 may adjust an impedance of the
target resonator 133 to modulate a signal to be transmitted to the
source device 110. For example, the controller 125 may increase the
impedance of the target resonator so that a reflected wave will be
detected by the controller 114 of the source device 110. In this
example, depending on whether the reflected wave is detected, the
controller 114 of the source device 110 will detect a binary number
"0" or "1".
The communication unit 124 may transmit, to the source device 110,
any one or any combination of a response message including a
product type of a corresponding target device, manufacturer
information of the corresponding target device, a product model
name of the corresponding target device, a battery type of the
corresponding target device, a charging scheme of the corresponding
target device, an impedance value of a load of the corresponding
target device, information about a characteristic of a target
resonator of the corresponding target device, information about a
frequency band used the corresponding target device, an amount of
power to be used by the corresponding target device, an intrinsic
identifier of the corresponding target device, product version
information of the corresponding target device, and standards
information of the corresponding target device.
The communication unit 124 may also perform an out-of-band
communication using a communication channel. The communication unit
124 may include a communication module, such as a ZigBee module, a
Bluetooth module, or any other communication module known in the
art, that the communication unit 124 may use to transmit or receive
data 140 to or from the source device 110 via the out-of-band
communication.
The communication unit 124 may receive a wake-up request message
from the source device 110, detect an amount of a power received by
the target resonator, and transmit, to the source device 110,
information about the amount of the power received by the target
resonator. In this example, the information about the amount of the
power received by the target resonator may correspond to an input
voltage value and an input current value of the rectification unit
122, an output voltage value and an output current value of the
rectification unit 122, or an output voltage value and an output
current value of the DC/DC converter 123.
FIG. 2 is a diagram illustrating an example of a wireless charging
environment for a wireless power transmission apparatus. Referring
to FIG. 2, a three-dimensional (3D) wireless charging environment
is shown, in which power transmission from a single source device
to target devices disposed at various locations and directions is
performed. In the 3D wireless charging environment, a target device
may need to be charged with an efficiency greater than or equal to
a predetermined efficiency although the target device is disposed
at a random distance and a random direction, other than a
predetermined distance and a predetermined direction, from the
source device.
FIG. 3 is a block diagram illustrating an example of a wireless
power transmission apparatus. Referring to FIG. 3, the wireless
power transmission apparatus includes a power transmitting unit
310, a feeding unit 320 (e.g., a feeder), a controller 330, and a
communication unit 340.
The power transmitting unit 310 includes source resonators 311,
313, and 315 that transmit a power wirelessly to a target resonator
(e.g., the target resonator 133 of FIG. 1) via magnetic coupling
between the target resonator and the source resonators 311, 313,
and 315. Although three source resonators are illustrated in FIG.
3, a number of source resonators is not limited thereto. At least
two source resonators may be included in the power transmitting
unit 310. The source resonators 311, 313, and 315 may be arranged
in a coupled form or a separated form. An example of the coupled
form is illustrated in FIGS. 6 and 7, and an example of the
separated form is illustrated in FIG. 10.
The feeding unit 320 provides a power to each of the source
resonators 311, 313, and 315. The feeding unit 320 may transfer, to
the each of the source resonators 311, 313, and 315, a power
supplied from a power supply.
The controller 330 controls a current magnitude and/or a voltage
magnitude of the power to be provided by the feeding unit 320. The
controller 330 may control a current magnitude and/or a voltage
magnitude of the power supplied from the power supply. The
controlled power may be supplied from the power supply to the
feeding unit 320, and the feeding unit 320 may transfer the
supplied power to each of the source resonators 311, 313, and
315.
For example, the controller 330 may calculate an impedance
parameter of an N-port network (e.g., as shown in FIG. 5) between
the target resonator connected to an output end of the N-port
network and the source resonators 311, 313, and 315 connected to
respective input ends of the N-port network. The impedance
parameter may include parameters indicating various relationships
between the output and the input ends of the N-port network, for
example, a Z-parameter, an h-parameter, an a-parameter, a
b-parameter, and/or other parameters known to one of ordinary skill
in the art. The N-port network will be described in detail with
reference to FIG. 5. The controller 330 may control the current
magnitude and/or the voltage magnitude of the power to be provided
to each of the source resonators 311, 313, and 315 based on the
calculated impedance parameter.
The communication unit 340 may receive, from a wireless power
reception apparatus (e.g., the target device 120 of FIG. 1),
information of a voltage and/or a current that are applied to a
load of the wireless power reception apparatus when a test voltage
and a test current are applied to the source resonators 311, 313,
and 315. The communication unit 340 may receive, from the wireless
power reception apparatus, information of a power received at the
wireless power reception apparatus when a test power is applied to
the source resonators 311, 313, and 315. The information of the
power received may include information of a current and/or a
voltage that are received at the wireless power reception
apparatus. The communication unit 340 may communicate with the
wireless power reception apparatus, using an in-band communication
scheme and/or an out-band communication scheme.
For example, the controller 330 may control the current magnitude
and/or the voltage magnitude of the power to be provided to each of
the source resonators 311, 313, and 315 based on an efficiency of a
power transmission to the target resonator. The controller 330 may
calculate the power transmission efficiency based on the
information of the power received at the wireless power reception
apparatus. The information of the power may be received from the
wireless power reception apparatus through the communication unit
340.
In another example, the controller 330 may control the current
magnitude and/or the voltage magnitude of the power to be provided
to each of the source resonators 311, 313, and 315 in order to
satisfy a predetermined power transmission efficiency, e.g., a
desired value of the power transmission efficiency. For example, if
the power transmission efficiency is preset to 80%, the controller
330 may control the current magnitude and/or the voltage magnitude
in order to satisfy the power transmission efficiency of 80%. In
this example, the controller 330 may control the power at different
current magnitudes and/or different voltage magnitudes to be
provided to each of the source resonators 311, 313, and 315 or may
control the power at identical current magnitudes and/or identical
voltage magnitudes to be provided to each of the source resonators
311, 313, and 315.
The controller 330 controls a current phase and/or a voltage phase
of the power to be provided by the feeding unit 320. The controller
330 may control the current phase and/or the voltage phase of the
power to be provided to each of the source resonators 311, 313, and
315, based on the efficiency of the power transmission to the
target resonator. For example, the controller 330 may control the
current phase and/or the voltage phase in order to satisfy the
predetermined power transmission efficiency. In another example,
the controller 330 may control the current phase and/or the voltage
phase based on the calculated impedance parameter.
In more detail, each time the current magnitude and/or the voltage
magnitude is controlled, the controller 330 may receive, from the
communication unit 340, the information of the power received at
the wireless power reception apparatus, calculate the power
transmission efficiency based on the information of the power
received, and compare the calculated power transmission efficiency
to the predetermined power transmission efficiency. When the
calculated power transmission efficiency satisfies (e.g., is
greater than or equal to) the predetermined power transmission
efficiency, the controller 330 may determine the current magnitude
and/or the voltage magnitude to be an optimal current magnitude
and/or an optimal voltage magnitude of an optimal power to be
provided to each of the source resonators 311, 313, and 315.
Otherwise, the controller 330 may adjust the current magnitude
and/or the voltage magnitude.
Each time the current phase and/or the voltage phase is controlled,
the controller 330 may receive, from the communication unit 340,
the information of the power received at the wireless power
reception apparatus, calculate the power transmission efficiency
based on the information of the power received, and compare the
power transmission efficiency to the predetermined power
transmission efficiency. When the calculated power transmission
efficiency satisfies (e.g., is greater than or equal to) the
predetermined power transmission efficiency, the controller 330 may
determine the current phase and/or the voltage phase to be an
optimal current phase and/or an optimal voltage phase of an optimal
power to be provided to each of the source resonators 311, 313, and
315. Otherwise, the controller 330 may adjust the current phase
and/or the voltage phase.
The controller 330 may estimate the optimal current magnitude
and/or the optimal voltage magnitude, by performing a simulation
within an adjustable range of the current magnitude and/or the
voltage magnitude for each of the source resonators 311, 313, and
315. The simulation may correspond to a software measurement, and
be performed using an optimization algorithm and an optimization
tool. The controller 330 may determine the current magnitude and/or
the voltage magnitude used in the simulation to be the optimal
current magnitude and/or the optimal voltage magnitude. The
controller 330 may further estimate the optimal current phase
and/or the optimal voltage phase, by performing the simulation
within an adjustable range of the current phase and/or the voltage
phase for each of the source resonators 311, 313, and 315.
Although not shown in FIG. 3, each of the source resonators 311,
313, and 315 may include a first transmission line, a first
conductor, a second conductor, and a first capacitor. The first
transmission line may include a first signal conducting portion, a
second signal conducting portion, and a first ground conducting
portion corresponding to the first signal conducting portion and
the second signal conducting portion. The first conductor may
electrically connect the first signal conducting portion to the
first ground conducting portion. The second conductor may be spaced
from the first ground conducting portion, and may be electrically
connected to the second signal conducting portion. The first
capacitor may be inserted in series between the first signal
conducting portion and the second signal conducting portion, with
respect to a current flowing through the first signal conducting
portion and the second signal conducting portion. For example, each
of the source resonators 311, 313, and 315 may be provided in a
structure illustrated in FIGS. 14A and 14B.
FIG. 4 is a block diagram illustrating another example of a
wireless power transmission apparatus. Referring to FIG. 4, the
wireless power transmission apparatus includes a power transmitting
unit 410, a feeding unit 420 (e.g., a feeder), a controller 430,
and a communication unit 440.
The power transmitting unit 410 includes source resonators 411 and
413 that transmit a power wirelessly to a target resonator (e.g.,
the target resonator 133 of FIG. 1) via magnetic coupling between
the target resonator and the source resonators 411 and 413.
Although two source resonators are illustrated in FIG. 4, a number
of source resonators is not limited thereto. At least two source
resonators may be included in the power transmitting unit 410. The
source resonators 411 and 413 may be arranged in a coupled form or
a separated form. An example of the coupled form is illustrated in
FIGS. 6 and 7, and an example of the separated form is illustrated
in FIG. 10.
The feeding unit 420 provides a power to each of the source
resonators 411 and 413. The feeding unit 420 may transfer, to each
of the source resonators 411 and 413, a power supplied from a power
supply.
The controller 430 controls a current magnitude and/or a voltage
magnitude of the power to be provided by the feeding unit 420. The
controller 430 may control a current magnitude and/or a voltage
magnitude of the power supplied from the power supply. The
controlled power may be supplied from the power supply to the
feeding unit 420, and the feeding unit 420 may transfer the
supplied power to each of the source resonators 411 and 413.
For example, the controller 430 may calculate an impedance
parameter of an N-port network (e.g., as shown in FIG. 5) between
the target resonator connected to an output end of the N-port
network and the source resonators 411 and 413 connected to
respective input ends of the N-port network. The impedance
parameter may include parameters indicating various relationships
between the output and the input ends of the N-port network, for
example, a Z-parameter, an h-parameter, an a-parameter, a
b-parameter, and/or other parameters known to one of ordinary skill
in the art. The N-port network will be described in detail with
reference to FIG. 5. The controller 430 may control the current
magnitude and/or the voltage magnitude of the power to be provided
to each of the source resonators 411 and 413 based on the
calculated impedance parameter.
The communication unit 440 may receive, from a wireless power
reception apparatus (e.g., the target device 120 of FIG. 1),
information of a voltage and/or a current applied to a load of the
wireless power reception apparatus when a test voltage and a test
current are applied to the source resonators 411 and 413. The
communication unit 440 may receive, from the wireless power
reception apparatus, information of a power received at the
wireless power reception apparatus when a test power is applied to
the source resonators 411 and 413. The information of the power
received may include information of a current and/or a voltage that
are received at the wireless power reception apparatus. The
communication unit 440 may communicate with the wireless power
reception apparatus, using an in-band communication scheme and/or
an out-band communication scheme.
The controller 430 includes a calculation unit 431, an optimization
unit 433, and a determination unit 435. The calculation unit 431
calculates the impedance parameter of the N-port network, and an
efficiency of a power transmission to the target resonator, based
on the information of the current and/or the voltage that are
received at the wireless power reception apparatus. The information
of the current and/or the voltage may be received from the wireless
power reception apparatus through the communication unit 440. The
power transmission efficiency may be calculated by comparing (e.g.,
determining a ratio of) the power received at the wireless power
reception apparatus to the power transmitted by the power
transmitting unit 410. The calculation unit 431 may calculate the
received power based on the information of the current and/or the
voltage that is received from the wireless power reception
apparatus through the communication unit 440. The impedance
parameter may be calculated by applying a condition needed for
calculation to the input ends and the output end of the N-port
network, for each impedance parameter.
The optimization unit 433 may optimize the impedance parameter
calculated by the calculation unit 431 based on a predetermined
power transmission efficiency, e.g., a desired value of the power
transmission efficiency. When the impedance parameter is
calculated, the optimization unit 433 may estimate an optimal
current magnitude, an optimal voltage magnitude, an optimal current
phase, and/or an optimal voltage phase of when the power
transmission efficiency satisfies the predetermined power
transmission efficiency. Also, the optimization unit 433 may
estimate at least two of the optimal current magnitude, optimal the
voltage magnitude, the optimal current phase, and the optimal
voltage phase of when the power transmission efficiency satisfies
the predetermined power transmission efficiency.
To estimate the optimal values, for example, the optimization unit
433 may optimize the impedance parameter, by changing the current
magnitude and/or the voltage magnitude of the power to be provided
to each of the source resonators 411 and 413, sequentially, in a
range of the current magnitude and/or the voltage magnitude that is
applicable by the feeding unit 420. In another example, the
optimization unit 433 may optimize the impedance parameter, by
executing an optimization algorithm based on the impedance
parameter and the predetermined power transmission efficiency. In
this example, the optimization algorithm changes the current
magnitude and/or the voltage magnitude, sequentially, in the
applicable range of the current magnitude and/or the voltage
magnitude. In still another example, the optimization unit 433 may
optimize the impedance parameter, by changing the current magnitude
and/or the voltage magnitude of the power to be provided to each of
the source resonators 411 and 413, randomly, in the range of the
current magnitude and/or the voltage magnitude that is applicable
by the feeding unit 420.
In yet another example, the optimization unit 433 may optimize the
impedance parameter, by changing the current magnitude and/or the
voltage magnitude of the power to be provided to each of the source
resonators 411 and 413 based on a lookup table, in the range of the
current magnitude and/or the voltage magnitude that is applicable
by the feeding unit 420. The lookup table may include a current
magnitude, a voltage magnitude, a current phase, and a voltage
phase that are matched statistically for each power transmission
efficiency. Also, the lookup table may include statistic data for
examples in which conditions for power distribution and/or other
conditions known to one of ordinary skill in the art are
satisfied.
The optimization unit 433 may estimate the optimal current
magnitude and/or the optimal voltage magnitude of when the power
transmission efficiency satisfies the predetermined power
transmission efficiency, based on the impedance parameter and an
N-port matrix relational expression induced in the N-port network.
As conditions of the optimization algorithm, the N-port matrix
relation expression, the impedance parameter, and the predetermined
power transmission efficiency may be used.
The determination unit 435 determines the current magnitude, the
voltage magnitude, the current phase, and/or the voltage phase of
the power to be provided to each of the source resonators 411 and
413 based on (e.g., to be) a result of the optimizing. For example,
the result of the optimizing may include the optimal current
magnitude, the optimal voltage magnitude, the optimal current
phase, and/or the optimal voltage phase of when the power
transmission efficiency satisfies the predetermined power
transmission efficiency.
For example, the controller 430 may control the current magnitude
and/or the voltage magnitude of the power to be provided to each of
the source resonators 411 and 413 based on the power transmission
efficiency. In another example, the controller 430 may control the
current magnitude and/or the voltage magnitude in order to satisfy
the predetermined power transmission efficiency. In this example,
if the predetermined power transmission efficiency is preset to
80%, the controller 430 may control the current magnitude and/or
the voltage magnitude in order to satisfy the predetermined power
transmission efficiency of 80%. In this example, the controller 430
may control the power at different current magnitudes or different
voltage magnitudes, or may control the power at identical current
magnitudes or identical voltage magnitudes.
The controller 430 controls the current phase and/or the voltage
phase of the power to be provided by the feeding unit 420. The
controller 430 may control the current phase and/or the voltage
phase based on the power transmission efficiency. For example, the
controller 430 may control the current phase and/or the voltage
phase in order to satisfy the predetermined power transmission
efficiency.
FIG. 5 is a diagram illustrating an example of an N-port network of
a wireless power transmission apparatus. In FIG. 5, the N-port
network is for an example in which three source resonators and a
single target resonator are provided. A value of N of the N-port
network may be determined based on a number of input ends and a
number of output ends. When the three source resonators are
connected to respective input ends of the N-port network, and the
single target resonator is connected to an output end of the N-port
network, a 4-port network 550 is formed.
Referring to FIG. 5, the wireless power transmission apparatus
includes a power source 510, and the three source resonators
disposed at a first port 520, a second port 530, and a third port
540, respectively. The power source 510 provides a power to each of
the source resonators. The power source 510 is disposed at each of
ports V.sub.s1, V.sub.s2, and V.sub.s3. Z.sub.s1 denotes an
impedance of V.sub.s1, Z.sub.s2 denotes an impedance of V.sub.s2,
and Z.sub.s3 denotes an impedance of V.sub.s3.
A wireless power reception apparatus includes a target resonator
disposed at a fourth port 560, and a load. V.sub.4 denotes a
voltage applied to the target resonator and the load, I.sub.4
denotes a current output from the target resonator, and Z.sub.load
denotes an impedance of the load.
V.sub.1 denotes a voltage applied to the first port 520, I.sub.1
denotes an output current, and Z.sub.in1 denotes an input impedance
of the first port 520. V.sub.2 denotes a voltage applied to the
second port 530, I.sub.2 denotes an output current, and Z.sub.in2
denotes an input impedance of the second port 530. V.sub.3 denotes
a voltage applied to the third port 540, I.sub.3 denotes an output
current, and Z.sub.in3 denotes an input impedance of the third port
540.
The input ends and the output end of the 4-port network 550 may be
expressed as a 4-port matrix relational expression using an
impedance parameter. For example, when Z denotes the impedance
parameter, the 4-port matrix relational expression may be arranged,
as given by the following example of Equation 1:
.function..times..times..times..times..times..times..times..times..times.-
.times..times..times..times..times..times..times..times..times..times..tim-
es..times..times..times..times..times..times..times..times.
##EQU00001##
Using Equation 1, a power transmission efficiency may be
calculated, as given by the following example of Equation 2:
.times..times..times..function..times..times..times..function..times..tim-
es..times..times..function..times..times..times..times..function..times..t-
imes. ##EQU00002##
In Equation 2, P.sub.avs denotes a power provided to each of the
source resonators, and P.sub.L denotes a power transferred to the
load. Referring to Equation 2, it may be understood that the power
transmission efficiency may be affected by an absolute value of the
current I.sub.4 flowing through the load, and an absolute value of
the voltage V.sub.s1, V.sub.s2, or V.sub.s3 provided to each of the
source resonators.
When a test power is provided by the power source 510, the
impedance parameter Z may be calculated. Using the calculated
impedance parameter Z, I.sub.4 may be expressed using a relational
expression of V.sub.s1, V.sub.s2, and V.sub.s3. Consequently, the
power transmission efficiency may be affected by the absolute value
of the voltage V.sub.s1, V.sub.s2, or V.sub.s3 provided to each of
the source resonators. The absolute value of the voltage V.sub.s1,
V.sub.s2, or V.sub.s3 may be determined based on a magnitude and a
phase of the voltage. Accordingly, the wireless power transmission
apparatus may adjust the magnitude and the phase of the voltage
provided to each of the source resonators, thereby adjusting the
power transmission efficiency.
A power to be provided to each of the source resonators may be
affected by a magnitude and a phase of a current flowing through
each of the source resonators. The wireless power transmission
apparatus may adjust the magnitude and the phase of the current
flowing through each of the source resonators, thereby adjusting
the power transmission efficiency. In addition, the wireless power
transmission apparatus may adjust the magnitude and/or the phase of
the current and/or the voltage that are applied to each of the
source resonators, thereby maintaining the power transmission
efficiency in a complex environment, such as, for example, a 3D
wireless charging environment.
FIG. 6 is a diagram illustrating an example of a target device 640
and a structure of resonators 610, 620, and 630 of a wireless power
transmission apparatus. Referring to FIG. 6, a power transmitting
unit of the wireless power transmission apparatus includes the
source resonators 610, 620, and 630. The source resonator 610
includes a surface parallel to an xy plane, the source resonator
620 includes a surface parallel to a yz plane, and the source
resonator 630 includes a surface parallel to a zx plane. The source
resonator 610, the source resonator 620, and the source resonator
630 are arranged in a coupled form, e.g., are physically-coupled to
each other.
The target device 640 receives a power wirelessly from the wireless
power transmission apparatus via magnetic coupling between the
target device 640 and the source resonators 610, 620, and 630. The
target device 640 may form an angle of 0 degrees with the source
resonators 610, 620, and 630 at a location of the target device
640. That is, the target device 640 is disposed to face the source
resonator 630. By adjusting a current magnitude, a current phase, a
voltage magnitude, and/or a voltage phase of a power to be provided
to each of the source resonators 610, 620, and 630, an efficiency
of a power transmission to the target device 640 may be maintained
to be greater than or equal to a predetermined power transmission
efficiency even if the location of the target device 640 is
changed.
Although three source resonators 610, 620, and 630 are provided in
FIG. 6, all examples of at least two resonators being provided may
be applicable. In addition, when a plurality of target devices is
provided, power distribution for each of the target device may be
adjusted by adjusting a current magnitude, a current phase, a
voltage magnitude, and/or a voltage phase of a power to be provided
to each of the source resonators.
FIG. 7 is a diagram illustrating another example of a target device
740 and a structure of resonators 710, 720, and 730 of a wireless
power transmission apparatus. Referring to FIG. 7, a power
transmitting unit of the wireless power transmission apparatus
includes the source resonators 710, 720, and 730 in the same
configuration as FIG. 6.
The target device 740 receives a power wirelessly from the wireless
power transmission apparatus via magnetic coupling between the
target device 740 and the source resonators 710, 720, and 730. The
target device 740 is disposed to form an angle of 30 degrees with
the source resonators 710, 720, and 730 at a location of the target
device 740. Similar to the example of FIG. 6, an efficiency of a
power transmission to the target device 740 may be maintained by
adjusting a current magnitude, a current phase, a voltage
magnitude, and/or a voltage phase of a power to be provided to each
of the source resonators 710, 720, and 730.
FIGS. 8 and 9 are graphs illustrating examples of a wireless power
transmission efficiency according to a voltage phase of a power to
be provided to a resonator by a wireless power transmission
apparatus. In more detail, FIG. 8 is a graph of an efficiency of a
power transmission from the source resonators 610, 620, and 630 to
the target device 640, in the example of FIG. 6. In this example, a
voltage magnitude of a power to be provided to each of the source
resonators 610, 620, and 630 is identical, and a voltage phase of
the power to be provided to each of the source resonators 620 and
630 (e.g., sources 2 and 3) is changed. The graph of FIG. 8 may be
generated through a simulation of changing the voltage phase of the
power to be provided to each of the source resonators 620 and
630.
As the voltage phase of the power to be provided to each of the
source resonators 620 and 630, is changed, the power transmission
efficiency is changed. In the graph of FIG. 8, the lower a
brightness, the higher the power transmission efficiency. It may be
estimated that the power transmission efficiency may be at a
maximum when the voltage phase 810 of the power to be provided to
the source resonator 620 is 70 degrees, and the voltage phase 820
of the of the power to be provided to the source resonator 630 is
100 degrees.
Although FIG. 8 illustrates the graph for the example in which the
voltage phase of the power to be provided to each of two source
resonators, is changed, a graph may be generated through a
simulation for an example in which a voltage phase of a power to be
provided to each of the three source resonators is changed, an
example in which a voltage magnitude of the power to be provided to
each of the three source resonators is changed, and/or an example
in which the voltage phase and the voltage magnitude of the power
to be provided to each of the three source resonators is
changed.
In more detail, FIG. 9 is a graph of an efficiency of a power
transmission from the source resonators 710, 720, and 730 to the
target device 740, in the example of FIG. 7. In this example, a
voltage magnitude of a power to be provided to each of the source
resonators 710, 720, and 730 is identical, and a voltage phase of
the power to be provided to each of the source resonators 720 and
730 (e.g., sources 2 and 3) is changed.
As the voltage phase of the power to be provided to each of the
source resonators 720 and 730, is changed, the power transmission
efficiency is changed. In the graph of FIG. 9, the lower a
brightness, the higher the power transmission efficiency. It may be
estimated that the power transmission efficiency may be at a
maximum when the voltage phase 910 of the power to be provided to
the source resonator 720 is 170 degrees, and the voltage phase 920
of the power to be provided to the source resonator 730 is 100
degrees.
FIG. 10 is a diagram illustrating an example of a target device
1030 and an arrangement of resonators 1010 and 1020 of a wireless
power transmission apparatus. Referring to FIG. 10, the source
resonators 1010 and 1020 are arranged in a separated form (e.g.,
are separated from each other), rather than a coupled form, even
though the source resonators 1010 and 1020 receive a power provided
from a feeding unit.
The target device 1030 receives a power wirelessly from the
wireless power transmission apparatus via magnetic coupling between
the target device 1030 and the source resonators 1010 and 1020. By
adjusting a current magnitude, a voltage magnitude, a current
phase, and/or a voltage phase of the power to be provided from the
feeding unit to each of the source resonators 1010 and 1020, an
efficiency of a power transmission to the target device 1030 may be
maintained to be greater than or equal to a predetermined power
transmission efficiency satisfying conditions needed to charge the
target device 1030.
FIG. 11 is a diagram illustrating an example of a structure of a
resonator of a wireless power transmission apparatus. Referring to
FIG. 11, the source resonator of the wireless power transmission
apparatus is a hexahedron. The source resonator includes source
resonators 1110 through 1160. The resonator 1110 includes a surface
parallel to a surface of the resonator 1140, the resonator 1120
includes a surface parallel to a surface of the resonator 1150, and
the resonator 1130 includes a surface parallel to a surface of the
resonator 1160.
FIG. 12 is a flowchart illustrating an example of a wireless power
transmission method. Referring to FIG. 12, in operation 1210, a
wireless power transmission apparatus controls a current magnitude
and/or a voltage magnitude of a power to be provided to each of
source resonators. For example, the wireless power transmission
apparatus may control the current magnitude, the voltage magnitude,
a current phase, and/or a voltage phase of the power to be supplied
to each of the source resonators based on an efficiency of a power
transmission to a target resonator of a wireless power reception
apparatus.
In another example, the wireless power transmission apparatus may
calculate an impedance parameter of an N-port network between the
target resonator connected to an output end of the N-port network
and the source resonators connected to respective input ends of the
N-port network. The wireless power transmission apparatus may
control the current magnitude and/or the voltage magnitude of the
power to be provided to each of the source resonators based on the
calculated impedance parameter.
In still another example, the wireless power transmission apparatus
may receive, from a wireless power reception apparatus, information
of a current and/or a voltage that are applied to a load of the
wireless power reception apparatus when a test current and a test
voltage are applied to the source resonators. The wireless power
transmission apparatus may calculate the impedance parameter of the
N-port network, and the power transmission efficiency, based on the
received information of the current and/or the voltage.
In yet another example, the wireless power transmission apparatus
may optimize the impedance parameter based on a predetermined power
transmission efficiency, e.g., a desired value of the power
transmission efficiency. The wireless power transmission apparatus
may determine the current magnitude and/or the voltage magnitude of
the power to be provided to each of the source resonators based on
a result of the optimizing.
In operation 1220, the wireless power transmission apparatus
provides the power to each of the source resonators. The wireless
power transmission apparatus may provide the power to each of the
source resonators through a feeder.
In operation 1230, the wireless power transmission apparatus
transmits a power wirelessly to the wireless power reception
apparatus via magnetic coupling between the target resonator and
the source resonators. The wireless power transmission apparatus
may adjust the voltage magnitude, the voltage phase, the current
magnitude, and/or the current phase that are applied to each of the
source resonators, thereby adjusting the power transmission
efficiency.
In the following description, the term "resonator" used in the
discussion of FIGS. 13A through 16 refers to both a source
resonator and a target resonator. Resonators of FIGS. 13A through
16 may be applied to the resonators of FIGS. 1 through 12.
FIGS. 13A and 13B are diagrams illustrating examples of a
distribution of a magnetic field in a feeder and a resonator of a
wireless power transmitter. When a resonator receives power
supplied through a separate feeder, magnetic fields are formed in
both the feeder and the resonator.
FIG. 13A illustrates an example of a structure of a wireless power
transmitter in which a feeder 1310 and a resonator 1320 do not
include a common ground. Referring to FIG. 13A, as an input current
flows into a feeder 1310 through a terminal labeled "+" and out of
the feeder 1310 through a terminal labeled "-", a magnetic field
1330 is formed by the input current. A direction 1331 of the
magnetic field 1330 inside the feeder 1310 is into the plane of
FIG. 13A, and includes a phase that is opposite to a phase of a
direction 1333 of the magnetic field 1330 outside the feeder 1310.
The magnetic field 1330 formed by the feeder 1310 induces a current
to flow in a resonator 1320. The direction of the induced current
in the resonator 1320 is opposite to a direction of the input
current in the feeder 1310 as indicated by the dashed arrows in
FIG. 13A.
The induced current in the resonator 1320 forms a magnetic field
1340. Directions of the magnetic field 1340 are the same at all
positions inside the resonator 1320. Accordingly, a direction 1341
of the magnetic field 1340 formed by the resonator 1320 inside the
feeder 1310 includes the same phase as a direction 1343 of the
magnetic field 1340 formed by the resonator 1320 outside the feeder
1310.
Consequently, when the magnetic field 1330 formed by the feeder
1310 and the magnetic field 1340 formed by the resonator 1320 are
combined, a strength of the total magnetic field inside the
resonator 1320 decreases inside the feeder 1310 and increases
outside the feeder 1310. In an example in which power is supplied
to the resonator 1320 through the feeder 1310 configured as
illustrated in FIG. 13A, the strength of the total magnetic field
decreases in the center of the resonator 1320, but increases
outside the resonator 1320. In another example in which a magnetic
field is randomly distributed in the resonator 1320, it is
difficult to perform impedance matching since an input impedance
will frequently vary. Additionally, when the strength of the total
magnetic field increases, an efficiency of wireless power
transmission increases. Conversely, when the strength of the total
magnetic field is decreases, the efficiency of wireless power
transmission decreases. Accordingly, the power transmission
efficiency may be reduced on average.
FIG. 13B illustrates an example of a structure of a wireless power
transmitter in which a resonator 1350 and a feeder 1360 include a
common ground. The resonator 1350 includes a capacitor 1351. The
feeder 1360 receives a radio frequency (RF) signal via a port 1361.
When the RF signal is input to the feeder 1360, an input current is
generated in the feeder 1360. The input current flowing in the
feeder 1360 forms a magnetic field, and a current is induced in the
resonator 1350 by the magnetic field. Additionally, another
magnetic field is formed by the induced current flowing in the
resonator 1350. In this example, a direction of the input current
flowing in the feeder 1360 includes a phase opposite to a phase of
a direction of the induced current flowing in the resonator 1350.
Accordingly, in a region between the resonator 1350 and the feeder
1360, a direction 1371 of the magnetic field formed by the input
current includes the same phase as a direction 1373 of the magnetic
field formed by the induced current, and thus the strength of the
total magnetic field increases in the region between the resonator
1350 and the feeder 1360. Conversely, inside the feeder 1360, a
direction 1381 of the magnetic field formed by the input current
includes a phase opposite to a phase of a direction 1383 of the
magnetic field formed by the induced current, and thus the strength
of the total magnetic field decreases inside the feeder 1360.
Therefore, the strength of the total magnetic field decreases in
the center of the resonator 1350, but increases outside the
resonator 1350.
An input impedance may be adjusted by adjusting an internal area of
the feeder 1360. The input impedance refers to an impedance viewed
in a direction from the feeder 1360 to the resonator 1350. When the
internal area of the feeder 1360 is increased, the input impedance
is increased. Conversely, when the internal area of the feeder 1360
is decreased, the input impedance is decreased. Because the
magnetic field is randomly distributed in the resonator 1350
despite a reduction in the input impedance, a value of the input
impedance may vary based on a location of a target device.
Accordingly, a separate matching network may be required to match
the input impedance to an output impedance of a power amplifier.
For example, when the input impedance is increased, a separate
matching network may be used to match the increased input impedance
to a relatively low output impedance of the power amplifier.
FIGS. 14A and 14B are diagrams illustrating an example of a feeding
unit and a resonator of a wireless power transmitter. Referring to
FIG. 14A, the wireless power transmitter includes a resonator 1410
and a feeding unit 1420. The resonator 1410 further includes a
capacitor 1411. The feeding unit 1420 is electrically connected to
both ends of the capacitor 1411.
FIG. 14B illustrates, in greater detail, a structure of the
wireless power transmitter of FIG. 14A. The resonator 1410 includes
a first transmission line (not identified by a reference numeral in
FIG. 14B, but formed by various elements in FIG. 14B as discussed
below), a first conductor 1441, a second conductor 1442, and at
least one capacitor 1450.
The capacitor 1450 is inserted in series between a first signal
conducting portion 1431 and a second signal conducting portion
1432, causing an electric field to be confined within the capacitor
1450. Generally, a transmission line includes at least one
conductor in an upper portion of the transmission line, and at
least one conductor in a lower portion of first transmission line.
A current may flow through the at least one conductor disposed in
the upper portion of the first transmission line, and the at least
one conductor disposed in the lower portion of the first
transmission line may be electrically grounded. In this example, a
conductor disposed in an upper portion of the first transmission
line in FIG. 14B is separated into two portions that will be
referred to as the first signal conducting portion 1431 and the
second signal conducting portion 1432. A conductor disposed in a
lower portion of the first transmission line in FIG. 14B will be
referred to as a first ground conducting portion 1433.
As illustrated in FIG. 14B, the resonator 1410 includes a generally
two-dimensional (2D) structure. The first transmission line
includes the first signal conducting portion 1431 and the second
signal conducting portion 1432 in the upper portion of the first
transmission line, and includes the first ground conducting portion
1433 in the lower portion of the first transmission line. The first
signal conducting portion 1431 and the second signal conducting
portion 1432 are disposed to face the first ground conducting
portion 1433. A current flows through the first signal conducting
portion 1431 and the second signal conducting portion 1432.
One end of the first signal conducting portion 1431 is connected to
one end of the first conductor 1441, the other end of the first
signal conducting portion 1431 is connected to the capacitor 1450,
and the other end of the first conductor 1441 is connected to one
end of the first ground conducting portion 1433. One end of the
second signal conducting portion 1432 is connected to one end of
the second conductor 1442, the other end of the second signal
conducting portion 1432 is connected to the other end of the
capacitor 1450, and the other end of the second conductor 1442 is
connected to the other end of the first ground conducting portion
1433. Accordingly, the first signal conducting portion 1431, the
second signal conducting portion 1432, the first ground conducting
portion 1433, the first conductor 1441, and the second conductor
1442 are connected to each other, causing the resonator 1410 to
include an electrically closed loop structure. The term "loop
structure" includes a polygonal structure, a circular structure, a
rectangular structure, and any other geometrical structure that is
closed, i.e., that does not include any opening in its perimeter.
The expression "including a loop structure" indicates a structure
that is electrically closed.
The capacitor 1450 is inserted into an intermediate portion of the
first transmission line. In the example in FIG. 14B, the capacitor
1450 is inserted into a space between the first signal conducting
portion 1431 and the second signal conducting portion 1432. The
capacitor 1450 may be a lumped element capacitor, a distributed
capacitor, or any other type of capacitor known to one of ordinary
skill in the art. For example, a distributed element capacitor may
include a zigzagged conductor line and a dielectric material
including a relatively high permittivity disposed between parallel
portions of the zigzagged conductor line.
The capacitor 1450 inserted into the first transmission line may
cause the resonator 1410 to include a characteristic of a
metamaterial. A metamaterial is a material including a
predetermined electrical property that is not found in nature, and
thus may include an artificially designed structure. All materials
existing in nature include a magnetic permeability and
permittivity. Most materials include a positive magnetic
permeability and/or a positive permittivity.
For most materials, a right-hand rule may be applied to an electric
field, a magnetic field, and a Poynting vector of the materials, so
the materials may be referred to as right-handed materials (RHMs).
However, a metamaterial that includes a magnetic permeability
and/or a permittivity that is not found in nature, and may be
classified into an epsilon negative (ENG) material, a mu negative
(MNG) material, a double negative (DNG) material, a negative
refractive index (NRI) material, a left-handed (LH) material, and
other metamaterial classifications known to one of ordinary skill
in the art based on a sign of the magnetic permeability of the
metamaterial and a sign of the permittivity of the
metamaterial.
If the capacitor 1450 is a lumped element capacitor and a
capacitance of the capacitor 1450 is appropriately determined, the
resonator 1410 may include a characteristic of a metamaterial. If
the resonator 1410 is caused to include a negative magnetic
permeability by appropriately adjusting the capacitance of the
capacitor 1450, the resonator 1410 may also be referred to as an
MNG resonator. Various criteria may be applied to determine the
capacitance of the capacitor 1450. For example, the various
criteria may include a criterion for enabling the resonator 1410 to
include the characteristic of the metamaterial, a criterion for
enabling the resonator 1410 to include a negative magnetic
permeability at a target frequency, a criterion for enabling the
resonator 1410 to include a zeroth order resonance characteristic
at the target frequency, and any other suitable criterion. Based on
any one or any combination of the aforementioned criteria, the
capacitance of the capacitor 1450 may be appropriately
determined.
The resonator 1410, hereinafter referred to as the MNG resonator
1410, may include a zeroth order resonance characteristic of
including a resonance frequency when a propagation constant is "0".
If the MNG resonator 1410 includes the zeroth order resonance
characteristic, the resonance frequency is independent of a
physical size of the MNG resonator 1410. By changing the
capacitance of the capacitor 1450, the resonance frequency of the
MNG resonator 1410 may be changed without changing the physical
size of the MNG resonator 1410.
In a near field, the electric field is concentrated in the
capacitor 1450 inserted into the first transmission line, causing
the magnetic field to become dominant in the near field. The MNG
resonator 1410 includes a relatively high Q-factor when the
capacitor 1450 is a lumped element, thereby increasing a power
transmission efficiency. The Q-factor indicates a level of an ohmic
loss or a ratio of a reactance with respect to a resistance in the
wireless power transmission. As will be understood by one of
ordinary skill in the art, the efficiency of the wireless power
transmission will increase as the Q-factor increases.
Although not illustrated in FIG. 14B, a magnetic core passing
through the MNG resonator 1410 may be provided to increase a power
transmission distance.
Referring to FIG. 14B, the feeding unit 1420 includes a second
transmission line (not identified by a reference numeral in FIG.
14B, but formed by various elements in FIG. 14B as discussed
below), a third conductor 1471, a fourth conductor 1472, a fifth
conductor 1481, and a sixth conductor 1482.
The second transmission line includes a third signal conducting
portion 1461 and a fourth signal conducting portion 1462 in an
upper portion of the second transmission line, and includes a
second ground conducting portion 1463 in a lower portion of the
second transmission line. The third signal conducting portion 1461
and the fourth signal conducting portion 1462 are disposed to face
the second ground conducting portion 1463. A current flows through
the third signal conducting portion 1461 and the fourth signal
conducting portion 1462.
One end of the third signal conducting portion 1461 is connected to
one end of the third conductor 1471, the other end of the third
signal conducting portion 1461 is connected to one end of the fifth
conductor 1481, and the other end of the third conductor 1471 is
connected to one end of the second ground conducting portion 1463.
One end of the fourth signal conducting portion 1462 is connected
to one end of the fourth conductor 1472, the other end of the
fourth signal conducting portion 1462 is connected to one end the
sixth conductor 1482, and the other end of the fourth conductor
1472 is connected to the other end of the second ground conducting
portion 1463. The other end of the fifth conductor 1481 is
connected to the first signal conducting portion 1431 at or near
where the first signal conducting portion 1431 is connected to one
end of the capacitor 1450, and the other end of the sixth conductor
1482 is connected to the second signal conducting portion 1432 at
or near where the second signal conducting portion 1432 is
connected to the other end of the capacitor 1450. Thus, the fifth
conductor 1481 and the sixth conductor 1482 are connected in
parallel to both ends of the capacitor 1450. The fifth conductor
1481 and the sixth conductor 1482 are used as an input port to
receive an RF signal as an input.
Accordingly, the third signal conducting portion 1461, the fourth
signal conducting portion 1462, the second ground conducting
portion 1463, the third conductor 1471, the fourth conductor 1472,
the fifth conductor 1481, the sixth conductor 1482, and the
resonator 1410 are connected to each other, causing the resonator
1410 and the feeding unit 1420 to include an electrically closed
loop structure. The term "loop structure" includes a polygonal
structure, a circular structure, a rectangular structure, and any
other geometrical structure that is closed, i.e., that does not
include any opening in its perimeter. The expression "including a
loop structure" indicates a structure that is electrically
closed.
If an RF signal is input to the fifth conductor 1481 or the sixth
conductor 1482, input current flows through the feeding unit 1420
and the resonator 1410, generating a magnetic field that induces a
current in the resonator 1410. A direction of the input current
flowing through the feeding unit 1420 is identical to a direction
of the induced current flowing through the resonator 1410, thereby
causing a strength of a total magnetic field to increase in the
center of the resonator 1410, and decrease near the outer periphery
of the resonator 1410.
An input impedance is determined by an area of a region between the
resonator 1410 and the feeding unit 1420. Accordingly, a separate
matching network used to match the input impedance to an output
impedance of a power amplifier may not be necessary. However, if a
matching network is used, the input impedance may be adjusted by
adjusting a size of the feeding unit 1420, and accordingly a
structure of the matching network may be simplified. The simplified
structure of the matching network may reduce a matching loss of the
matching network.
The second transmission line, the third conductor 1471, the fourth
conductor 1472, the fifth conductor 1481, and the sixth conductor
1482 of the feeding unit may include a structure identical to the
structure of the resonator 1410. For example, if the resonator 1410
includes a loop structure, the feeding unit 1420 may also include a
loop structure. As another example, if the resonator 1410 includes
a circular structure, the feeding unit 1420 may also include a
circular structure.
FIG. 15A is a diagram illustrating an example of a distribution of
a magnetic field in a resonator that is produced by feeding of a
feeding unit, of a wireless power transmitter. FIG. 15A more simply
illustrates the resonator 1410 and the feeding unit 1420 of FIGS.
14A and 14B, and the names of the various elements in FIG. 14B will
be used in the following description of FIG. 15A without reference
numerals.
A feeding operation may be an operation of supplying power to a
source resonator in wireless power transmission, or an operation of
supplying AC power to a rectifier in wireless power transmission.
FIG. 15A illustrates a direction of input current flowing in the
feeding unit, and a direction of induced current flowing in the
source resonator. Additionally, FIG. 15A illustrates a direction of
a magnetic field formed by the input current of the feeding unit,
and a direction of a magnetic field formed by the induced current
of the source resonator.
Referring to FIG. 15A, the fifth conductor or the sixth conductor
of the feeding unit 1420 may be used as an input port 1510. In FIG.
15A, the sixth conductor of the feeding unit is being used as the
input port 1510. An RF signal is input to the input port 1510. The
RF signal may be output from a power amplifier. The power amplifier
may increase and decrease an amplitude of the RF signal based on a
power requirement of a target device. The RF signal input to the
input port 1510 is represented in FIG. 15A as an input current
flowing in the feeding unit. The input current flows in a clockwise
direction in the feeding unit along the second transmission line of
the feeding unit. The fifth conductor and the sixth conductor of
the feeding unit are electrically connected to the resonator. The
fifth conductor of the feeding unit is connected to the first
signal conducting portion of the resonator, and the sixth conductor
of the feeding unit is connected to the second signal conducting
portion of the resonator. Accordingly, the input current flows in
both the resonator and the feeding unit. The input current flows in
a counterclockwise direction in the resonator along the first
transmission line of the resonator. The input current flowing in
the resonator generates a magnetic field, and the magnetic field
induces a current in the resonator due to the magnetic field. The
induced current flows in a clockwise direction in the resonator
along the first transmission line of the resonator. The induced
current in the resonator transfers energy to the capacitor of the
resonator, and also generates a magnetic field. In FIG. 15A, the
input current flowing in the feeding unit and the resonator is
indicated by solid lines with arrowheads, and the induced current
flowing in the resonator is indicated by dashed lines with
arrowheads.
A direction of a magnetic field generated by a current is
determined based on the right-hand rule. As illustrated in FIG.
15A, within the feeding unit, a direction 1521 of the magnetic
field generated by the input current flowing in the feeding unit is
identical to a direction 1523 of the magnetic field generated by
the induced current flowing in the resonator. Accordingly, a
strength of the total magnetic field may increases inside the
feeding unit.
In contrast, as illustrated in FIG. 15A, in a region between the
feeding unit and the resonator, a direction 1533 of the magnetic
field generated by the input current flowing in the feeding unit is
opposite to a direction 1531 of the magnetic field generated by the
induced current flowing in the resonator. Accordingly, the strength
of the total magnetic field decreases in the region between the
feeding unit and the resonator.
Typically, in a resonator including a loop structure, a strength of
a magnetic field decreases in the center of the resonator, and
increases near an outer periphery of the resonator. However,
referring to FIG. 15A, since the feeding unit is electrically
connected to both ends of the capacitor of the resonator, the
direction of the induced current in the resonator is identical to
the direction of the input current in the feeding unit. Since the
direction of the induced current in the resonator is identical to
the direction of the input current in the feeding unit, the
strength of the total magnetic field increases inside the feeding
unit, and decreases outside the feeding unit. As a result, due to
the feeding unit, the strength of the total magnetic field
increases in the center of the resonator including the loop
structure, and decreases near an outer periphery of the resonator,
thereby compensating for the normal characteristic of the resonator
including the loop structure in which the strength of the magnetic
field decreases in the center of the resonator, and increases near
the outer periphery of the resonator. Thus, the strength of the
total magnetic field may be constant inside the resonator.
A power transmission efficiency for transferring wireless power
from a source resonator to a target resonator is proportional to
the strength of the total magnetic field generated in the source
resonator. Accordingly, when the strength of the total magnetic
field increases inside the source resonator, the power transmission
efficiency also increases.
FIG. 15B is a diagram illustrating examples of equivalent circuits
of a feeding unit and a resonator of a wireless power transmitter.
Referring to FIG. 15B, a feeding unit 1540 and a resonator 1550 may
be represented by the equivalent circuits in FIG. 15B. The feeding
unit 1540 is represented as an inductor including an inductance
L.sub.f, and the resonator 1550 is represented as a series
connection of an inductor including an inductance L coupled to the
inductance L.sub.f of the feeding unit 1540 by a mutual inductance
M, a capacitor including a capacitance C, and a resistor including
a resistance R. An example of an input impedance Z.sub.in viewed in
a direction from the feeding unit 1540 to the resonator 1550 may be
expressed by the following Equation 3:
.omega..times..times. ##EQU00003##
In Equation 3, M denotes a mutual inductance between the feeding
unit 1540 and the resonator 1550, .omega. denotes a resonance
frequency of the feeding unit 1540 and the resonator 1550, and Z
denotes an impedance viewed in a direction from the resonator 1550
to a target device. As can be seen from Equation 3, the input
impedance Z.sub.in is proportional to the square of the mutual
inductance M. Accordingly, the input impedance Z.sub.in may be
adjusted by adjusting the mutual inductance M. The mutual
inductance M depends on an area of a region between the feeding
unit 1540 and the resonator 1550. The area of the region between
the feeding unit 1540 and the resonator 1550 may be adjusted by
adjusting a size of the feeding unit 1540, thereby adjusting the
mutual inductance M and the input impedance Z.sub.in. Since the
input impedance Z.sub.in may be adjusted by adjusting the size of
the feeding unit 1540, it may be unnecessary to use a separate
matching network to perform impedance matching with an output
impedance of a power amplifier.
In a target resonator and a feeding unit included in a wireless
power receiver, a magnetic field may be distributed as illustrated
in FIG. 15A. For example, the target resonator may receive wireless
power from a source resonator via magnetic coupling. The received
wireless power induces a current in the target resonator. The
induced current in the target resonator generates a magnetic field,
which induces a current in the feeding unit. If the target
resonator is connected to the feeding unit as illustrated in FIG.
15A, a direction of the induced current flowing in the target
resonator will be identical to a direction of the induced current
flowing in the feeding unit. Accordingly, for the reasons discussed
above in connection with FIG. 15A, a strength of the total magnetic
field will increase inside the feeding unit, and will decrease in a
region between the feeding unit and the target resonator.
FIG. 16 is a diagram illustrating an example of an electric vehicle
charging system. Referring to FIG. 16, an electric vehicle charging
system 1600 includes a source system 1610, a source resonator 1620,
a target resonator 1630, a target system 1640, and an electric
vehicle battery 1650.
In one example, the electric vehicle charging system 1600 includes
a structure similar to the structure of the wireless power
transmission system of FIG. 1. The source system 1610 and the
source resonator 1620 in the electric vehicle charging system 1600
operate as a source. The target resonator 1630 and the target
system 1640 in the electric vehicle charging system 1600 operate as
a target.
In one example, the source system 1610 includes an alternating
current-to-direct current (AC/DC) converter, a power detector, a
power converter, a control and communication
(control/communication) unit similar to those of the source device
110 of FIG. 1. In one example, the target system 1640 includes a
rectifier, a DC-to-DC (DC/DC) converter, a switch, a charging unit,
and a control/communication unit similar to those of the target
device 120 of FIG. 1. The electric vehicle battery 1650 is charged
by the target system 1640. The electric vehicle charging system
1600 may use a resonant frequency in a band of a few kHz to tens of
MHz.
The source system 1610 generates power based on a type of the
vehicle being charged, a capacity of the electric vehicle battery
1650, and a charging state of the electric vehicle battery 1650,
and wirelessly transmits the generated power to the target system
1640 via a magnetic coupling between the source resonator 1620 and
the target resonator 1630.
The source system 1610 may control an alignment of the source
resonator 1620 and the target resonator 1630. For example, when the
source resonator 1620 and the target resonator 1630 are not
aligned, the controller of the source system 1610 may transmit a
message to the target system 1640 to control the alignment of the
source resonator 1620 and the target resonator 1630.
For example, when the target resonator 1630 is not located in a
position enabling maximum magnetic coupling, the source resonator
1620 and the target resonator 1630 are not properly aligned. When a
vehicle does not stop at a proper position to accurately align the
source resonator 1620 and the target resonator 1630, the source
system 1610 may instruct a position of the vehicle to be adjusted
to control the source resonator 1620 and the target resonator 1630
to be aligned. However, this is just an example, and other methods
of aligning the source resonator 1620 and the target resonator 1630
may be used.
The source system 1610 and the target system 1640 may transmit or
receive an ID of a vehicle and exchange various messages by
performing communication with each other.
The descriptions of FIGS. 1 through 15B are also applicable to the
electric vehicle charging system 1600. However, the electric
vehicle charging system 1600 may use a resonant frequency in a band
of a few kHz to tens of MHz, and may wirelessly transmit power that
is equal to or higher than tens of watts to charge the electric
vehicle battery 1650.
The examples of a wireless power transmission apparatus described
may adjust a current magnitude, a current phase, a voltage
magnitude, and/or a voltage phase of a power to be provided to a
resonator, thereby maintaining an optimal power transmission
efficiency in view of various environments, for example, a number
of devices to be charged, a location of a device to be charged, a
distance between a source resonator and a target resonator, and/or
a change in a location. Accordingly, the wireless power
transmission apparatus may control a magnetic field formed in the
resonator.
The wireless power transmission apparatus may be applied to an
example in which a source device or a target device is movable. For
example, if a source resonator and a target resonator are not
aligned while an electric vehicle is being charged wirelessly, a
power transmission efficiency may be maintained. The wireless power
transmission apparatus may adjust the current magnitude, the
current phase, the voltage magnitude, and/or the voltage phase of
the power to be provided to the resonator, thereby reducing a
number of matching networks.
The various units, modules, elements, and methods described above
may be implemented using one or more hardware components, one or
more software components, or a combination of one or more hardware
components and one or more software components.
A hardware component may be, for example, a physical device that
physically performs one or more operations, but is not limited
thereto. Examples of hardware components include microphones,
amplifiers, low-pass filters, high-pass filters, band-pass filters,
analog-to-digital converters, digital-to-analog converters, and
processing devices.
A software component may be implemented, for example, by a
processing device controlled by software or instructions to perform
one or more operations, but is not limited thereto. A computer,
controller, or other control device may cause the processing device
to run the software or execute the instructions. One software
component may be implemented by one processing device, or two or
more software components may be implemented by one processing
device, or one software component may be implemented by two or more
processing devices, or two or more software components may be
implemented by two or more processing devices.
A processing device may be implemented using one or more
general-purpose or special-purpose computers, such as, for example,
a processor, a controller and an arithmetic logic unit, a digital
signal processor, a microcomputer, a field-programmable array, a
programmable logic unit, a microprocessor, or any other device
capable of running software or executing instructions. The
processing device may run an operating system (OS), and may run one
or more software applications that operate under the OS. The
processing device may access, store, manipulate, process, and
create data when running the software or executing the
instructions. For simplicity, the singular term "processing device"
may be used in the description, but one of ordinary skill in the
art will appreciate that a processing device may include multiple
processing elements and multiple types of processing elements. For
example, a processing device may include one or more processors, or
one or more processors and one or more controllers. In addition,
different processing configurations are possible, such as parallel
processors or multi-core processors.
A processing device configured to implement a software component to
perform an operation A may include a processor programmed to run
software or execute instructions to control the processor to
perform operation A. In addition, a processing device configured to
implement a software component to perform an operation A, an
operation B, and an operation C may include various configurations,
such as, for example, a processor configured to implement a
software component to perform operations A, B, and C; a first
processor configured to implement a software component to perform
operation A, and a second processor configured to implement a
software component to perform operations B and C; a first processor
configured to implement a software component to perform operations
A and B, and a second processor configured to implement a software
component to perform operation C; a first processor configured to
implement a software component to perform operation A, a second
processor configured to implement a software component to perform
operation B, and a third processor configured to implement a
software component to perform operation C; a first processor
configured to implement a software component to perform operations
A, B, and C, and a second processor configured to implement a
software component to perform operations A, B, and C, or any other
configuration of one or more processors each implementing one or
more of operations A, B, and C. Although these examples refer to
three operations A, B, C, the number of operations that may
implemented is not limited to three, but may be any number of
operations required to achieve a desired result or perform a
desired task.
Software or instructions that control a processing device to
implement a software component may include a computer program, a
piece of code, an instruction, or some combination thereof, that
independently or collectively instructs or configures the
processing device to perform one or more desired operations. The
software or instructions may include machine code that may be
directly executed by the processing device, such as machine code
produced by a compiler, and/or higher-level code that may be
executed by the processing device using an interpreter. The
software or instructions and any associated data, data files, and
data structures may be embodied permanently or temporarily in any
type of machine, component, physical or virtual equipment, computer
storage medium or device, or a propagated signal wave capable of
providing instructions or data to or being interpreted by the
processing device. The software or instructions and any associated
data, data files, and data structures also may be distributed over
network-coupled computer systems so that the software or
instructions and any associated data, data files, and data
structures are stored and executed in a distributed fashion.
For example, the software or instructions and any associated data,
data files, and data structures may be recorded, stored, or fixed
in one or more non-transitory computer-readable storage media. A
non-transitory computer-readable storage medium may be any data
storage device that is capable of storing the software or
instructions and any associated data, data files, and data
structures so that they can be read by a computer system or
processing device. Examples of a non-transitory computer-readable
storage medium include read-only memory (ROM), random-access memory
(RAM), flash memory, CD-ROMs, CD-Rs, CD+Rs, CD-RWs, CD+RWs,
DVD-ROMs, DVD-Rs, DVD+Rs, DVD-RWs, DVD+RWs, DVD-RAMs, BD-ROMs,
BD-Rs, BD-R LTHs, BD-REs, magnetic tapes, floppy disks,
magneto-optical data storage devices, optical data storage devices,
hard disks, solid-state disks, or any other non-transitory
computer-readable storage medium known to one of ordinary skill in
the art.
Functional programs, codes, and code segments that implement the
examples disclosed herein can be easily constructed by a programmer
skilled in the art to which the examples pertain based on the
drawings and their corresponding descriptions as provided
herein.
As a non-exhaustive illustration only, a device described herein
may be a mobile device, such as a cellular phone, a personal
digital assistant (PDA), a digital camera, a portable game console,
an MP3 player, a portable/personal multimedia player (PMP), a
handheld e-book, a portable laptop PC, a global positioning system
(GPS) navigation device, a tablet, a sensor, or a stationary
device, such as a desktop PC, a high-definition television (HDTV),
a DVD player, a Blue-ray player, a set-top box, a home appliance,
or any other device known to one of ordinary skill in the art that
is capable of wireless communication and/or network
communication.
While this disclosure includes specific examples, it will be
apparent to one of ordinary skill in the art that various changes
in form and details may be made in these examples without departing
from the spirit and scope of the claims and their equivalents. The
examples described herein are to be considered in a descriptive
sense only, and not for purposes of limitation. Descriptions of
features or aspects in each example are to be considered as being
applicable to similar features or aspects in other examples.
Suitable results may be achieved if the described techniques are
performed in a different order, and/or if components in a described
system, architecture, device, or circuit are combined in a
different manner and/or replaced or supplemented by other
components or their equivalents. Therefore, the scope of the
disclosure is defined not by the detailed description, but by the
claims and their equivalents, and all variations within the scope
of the claims and their equivalents are to be construed as being
included in the disclosure.
* * * * *